I'll start with a: I'm brand new here and b: I have little experience with bees.

I wish to make a bee house for wild solitary bees. The idea is for an open source project designed to be built on any type of 3D printer - although I believe FDM printing with PLA would be best as the material is natural and to a degree biodegradable - not in the common sense, it doesn't vanish if left in the garden.

I have some questions, I've done lots of research but much of what I read seems to disagree with what is commercially available or what I have seen. I'm interested in knowing:

- the diameter of the tubes the bees would prefer to live in? I was thinking a range between 4mm to 10mm.

- should that diameter vary through the tube? Or does it not matter (how do they turn around for example?)

- I read the bees do not like water, but do not mind cold. I was thinking of having the tubes angled slightly down to stop rain getting in in the first place.

- Do they need any form of ventilation to stop condensation build up other than the open front?

- Do they need to see and go straight to their hole? If there was one larger hole that hid many smaller tubes would they be happy to explore or is it that they really need to fly directly to their own hole?

I know that's a lot. Sorry Once I have the designs done I'll be sharing the files.

Fair enough But some people want the design to not be a 'bunch of sticks in a box' - feedback from a potential customer. With a 3D printer we can create any shape we want on the inside and wrap it in any shape we want on the outside.

In my experience plastic is not very good for solitary bees. I have tried both conventional plastic drinking straws and 'biodegradable' ones. They both suffer very badly from mold over the winter and my bees always choose natural homes over plastic when they have the choice. Paper straws however work very well.

Going back to the questions though, the mina one for me is the hole they enter by. Does it need to be a unique hole for each bee, would they be happy to use a common entrance? That would be a larger hole leading to a set of inner holes.

The wood or paper tubes I can resolve without spoiling the aesthetic. Oh, and if you'd like one to test I'd be happy to ship one when it's done. I'll be making a few that are basically finished but will look ugly.

Once the thing is proven and working I'll be releasing all the files etc open source.

If you can make it breathable out of something like wood pulp, brick dust or cement I see no reason why it wouldn't work. I hadn't realized regular 3D printers were that versatile yet. The only small problem mite be the binding agent, weather it produces any unpleasant gasses. But it sounds like there will be no real difference between what you are making and the blocks of wood with holes in I have used, I've seen other people use breeze blocks full of holes with the same success and the bees are happy enough living in the mortar between bricks.

As for the entrance, thats something I have been meaning to experiment with but haven't got around to yet. My guess though from watching the bees is they would prefer separate entrances. They are not always that bright and sometimes it takes them a couple of goes before they find their currant nest, so in the dark they mite have even more problems.

This is an interesting idea. After all not everyone has the skills, tools or inclination to make stuff by hand. And as long as these houses work for the bees it doesn't really matter what they look like or how they are made. If this gets people who wouldn't otherwise have these things for what ever reason to get them then I'm all for it.

I would make the diameter uniform. What diameter depends on the bees in your area. Maybe your prototype should have varying sized holes, say 3/8" down to 1/16". Also, six inches deep would be great. There a few species of solitary bees that lay the male eggs for the first few inches, then the female. All you get are males if the holes are only three inches deep.

I'm a bit skeptical of them excepting a plastic material, so the idea of straws or cardboard tubes would be worth exploring.

I can't imagine why anyone would want to use a 3D printer for this, when you can make a wild bee house using natural, renewable materials so easily, using only manual labour.

Not everybody has sufficient strength, use of their hands and arms, or eyesight to make something like this in the traditional way, but could use a computer and 3D printer to create one and to contribute to its development.

Thanks for the amazing replies, and I'm glad you like the idea. I'm sourcing some cardboard tubes in two sizes to suit and will be using these as replaceable sleeves inside the holes. The holes will themselves have channels to let air circulate so no condensation builds up. The first test prints will happen this weekend, they'll be crude and ugly but functional. I'll be looking for volunteers to test them out so if anyone wants one let me know.

I'll then be looking to offer CAD files and code for printing either a single unit separate pieces ready for mould making for mass production.

Really looking forward to this now. When is the best time to get these up ready for habitation?

I will be posting pictures. Had to abort the first test prints as I noticed a design flaw. Re-desinging now and will print today. I have to print in bits otherwise each one will take 79 hours which is too long for simple test objects.

I also decided the final ones will be multi part to allow changing of cardboard tubes and also so that they can be cast in ceramic etc.

Conserving wild bees

Research suggests that bumble bee boxes have a very low success rate in actually attracting bees into them. We find that if you create an environment where first of all you can attract mice inside, such as a pile of stones, a drystone wall, paving slabs with intentionally made cavities underneath, this will increase the success rate.

Most bumble bee species need a dry space about the size a football, with a narrow entrance tunnel approximately 2cm in diameter and 20 cm long. Most species nest underground along the base of a linear feature such as a hedge or wall. Sites need to be sheltered and out of direct sunlight.